Amos2
I didn't read
Metro's post but what you've said above gives;
1) the American flightplanning system of 're-file inflight', and
2) a modification of the Qantas system which gives A-B reliability in the high 90's.
At all times, the airlines state they're going A-B to the pax. it's how you stay legal with little fuel at the end that counts.
G'day
